Sanfilippo Syndrome Type CC-RARENCT07712003
Natural History to Assess Disease in Patients With MPS IIIC
An observational study of Sanfilippo Syndrome Type C and Mucopolysaccharidosis (MPS) IIIC, run by Phoenix Nest at 1 site in United States.
Trial summary
This is a REMOTE prospective observational study of participants with MPS IIIC. No investigational medicinal product will be administered as part of this study. Patients functional abilities will be captured using video recordings taken by patients legal representative or caregiver using a dedicated clinical video… Read more about this study
- Who is it for?
- Ages 1 year to 25 years
- Conditions the study is for
- Sanfilippo Syndrome Type C, Mucopolysaccharidosis (MPS) IIIC
- How many people
- 35 participants
- Where
- 1 siteUnited States
- Study dates
- 1 Nov 2026to 1 Feb 2029
- Phase
- Observational
- Are there results?
- Not yet: the study is under way
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 1 year to 25 years
- All sexes
- No healthy volunteers
- Child, Adult
Study population: The study population will include participants with confirmed diagnosis of MPS IIIC. Participants will be recruited for approximately 3 months by patient organizations. The patient organizations will provide participants with details of the site coordinator at University of Texas Southwestern (UTSW).
Who may be able to join
- 1. ≥1 year and ≤ 25 years of age 2. Confirmed diagnosis of MPS IIIC by all of the following:
- Deficiency in the Hgsnat enzyme activity
- Genetic analysis demonstrating homozygous or compound heterozygous, pathogenic, and/or potentially pathogenic variants in the Hgsnat gene
- Signs/symptoms consistent with MPS IIIC, or individuals who have not presented with signs/symptoms of disease but meet inclusion criteria 2a and 2b 3. Electronic informed consent from legal representative(s) or caregivers and when possible, pediatric or adult assent from the participant 4. One of the legal representative(s) or the caregivers is willing to perform at home visits and assessments per instruction 5. Ability to comply with protocol requirements, in the opinion of the Investigator 6. Able to take food or liquid by mouth, able to walk with or without assistance 7. Participants must have health insurance 8. Caregiver willing and able to comply with protocol requirements, including performing at-home visits and assessments 9. Participants must have smart phone or tablet and reliable internet connection 10. Have one of these languages as their first language: English, Spanish, French, German or Portuguese
Who cannot join
- Have received prior gene therapy or ERT for the treatment of MPS IIIC ever or any other investigational drug for any reason within 30 days prior to the Screening visit (Visit 1)
- Have concomitant illness or medical condition that, in the opinion of the Investigator, might compromise the participant's ability to comply with protocol requirements or the participant's wellbeing or safety, or the interpretability of the participant's clinical data
Trial locations and contacts
1 site in 1 country. Contact the study team or a site near you to ask about taking part.
Alyssa Boudreau contact
United States1 site
UT Southwestern Children's Medical Center
Dallas, Texas, 75235
Holly Lawrence, 214-456-9561, Holly.Lawrence@UTSouthwestern.edu
About this study
Official title: Observational Study to Assess Disease Symptoms and Progression in Participants With Sanfilippo Syndrome Type C (Mucopolysaccharidosis Type III [MPS III] C)
This is a REMOTE prospective observational study of participants with MPS IIIC.
No investigational medicinal product will be administered as part of this study.
Read more
Patients functional abilities will be captured using video recordings taken by patients legal representative or caregiver using a dedicated clinical video application downloaded from the internet onto a smartphone. The video application is called C-RARE.
Electronic observer-reported outcome (ObsRO) questionnaires will be completed by the legal representatives or caregivers via C-RARE.
The study will last two years with videos and questionnaires taken every 6 months for a total of 5 time points. Data will then be reviewed and measured for functional change using a scoring scale designed for the use of this study.
Read the detailed description
The study will be conducted remotely; no in-person visits are required. Approximately 35 participants with MPS IIIC will be enrolled in the study through a study site in the United States of America (USA). Enrollment of the first 25 participants with age ≤10 years will help ensure that the data collected from these younger participants will provide a better understanding of the early phase of the disease that may be relevant for future drug development. The remaining 10 participants will be between 11 to 25 years of age. The cutoff for the study is 25 years old. Participants speaking either Spanish, Portuguese, German, French or English may enroll in the study.
At Screening (Visit 1), the site coordinator based at UT Southwestern will review the laboratory report with a confirmed diagnosis of Hgsnat-deficiency MPS IIIC and a mutational analysis report demonstrating homozygous or compound heterozygous, pathogenic, and/or potentially pathogenic variants in the Hgsnat gene to assess the eligibility of the participants. After confirming diagnosis by the site coordinator, the caregiver or legal representative(s) will read and sign the informed consent form electronically, and when possible, the participant will provide adult or pediatric assent electronically.
At Baseline (Visit 2), the legal representative(s) or caregiver will be asked to complete electronic demographics and medical record questionnaire via the C-RARE App.
At Baseline (Visit 2) and at 6-month intervals (from Visit 3 through the end of the study), the legal representative(s) or caregiver will be asked to complete questionnaires and record home video assessments using a dedicated study app called C-RARE. Functional and cognitive abilities will be captured in the home environment by video and PEDI-CAT, an electronic a caregiver reported outcome assessment.
The legal representative(s) or caregiver will be provided with a C-RARE kit (via mailing), which includes a manual and props, as well as training for using the app. Baseline at-home visit (demographics, medical/surgical history, concomitant medications/therapy history, video and PEDI-CAT assessment, and ObsRO) should be completed at Visit 2. At-home Visit 3 to Visit 6 (video, PEDI-CAT assessment, and ObsRO) should be completed within a 14-day period for each visit. The legal representative(s) or caregiver will be provided with the timeline for each visit.
The study population will include participants with a confirmed diagnosis of MPS IIIC. Participants will be recruited for approximately 3 months by patient organizations. The patient organizations will provide participants with details of the site coordinator at UTSW. Participant-level data will be obtained through C-RARE app and PEDI-CAT.
- Keywords
- Mucopolysaccharidosis, Sanfilippo syndrome, MPS IIIC
- Medical subject headings
- Mucopolysaccharidosis III, Mucopolysaccharidoses
What is being measured
The primary outcome is the main question the study is designed to answer.
Daily living functions captured by video
Ability to perform activities of daily living.
Measured: Baseline to up to 2 years with 6-month time points.
Expressive and receptive language assessed by standard questionnaires
Ability to understand, comprehend and respond to communication.
Measured: Baseline to up to 2 years with 6-month time points.
Speech as assessed by standard questionnaires
Analysis of speech quality.
Measured: Baseline to up to 2 years; with 6-month time points.
Behavior as assessed by ability to perform daily functions as captured by video
Quality of behavior as defined by ability to perform defined functions
Measured: Baseline to up to 2 years with 6-month time points.
Mobility as assessed by video and standard questionnaires
Assessment of fine and gross motor abilities
Measured: Baseline up to 2 years with 6-month time points.
Secondary outcomes (3)
What Matters Most
Questionnaire asking caregiver to rank skills from most important to least
Measured: Baseline up to 2years with 6-month time points.
Assessment of Behavioral Changes in Sanfilippo (ABCS)
Questionnaire asking families to rank changes in patients behavior over time.
Measured: Baseline up to 2 years with 6-month time points.
PEDI-CAT standard questionnaire
Observer reporter cognitive outcome questionnaire
Measured: Baseline up to 2 years with 6-month time points.
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted17 Jul 2026
- Study start1 Nov 2026 (estimated)
- Primary completion1 Nov 2028 (estimated)
- Study completion1 Feb 2029 (estimated)
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for Sanfilippo Syndrome Type CStudies of the same condition, open and under way.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Observational
- Observational model
- Case only
- Time perspective
- Prospective
- Enrolment
- 35 participants (estimated)
Sponsor and investigators
- Lead sponsor
- Phoenix Nest
- Sponsor type
- Industry (pharma, biotech, devices)
- Collaborators
- National Institutes of Health (NIH)
- Responsible party
- Sponsor
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT07712003
- Sponsor's protocol ID
- JLK-448
- Acronym
- C-RARE
- Status last verified
- Jul 2026
- First submitted
- 15 Jun 2026
- Last updated
- 17 Jul 2026
- Results posted
- No
- Data monitoring committee
- Yes
- FDA-regulated drug
- No
- FDA-regulated device
- No
- Individual data sharing
- Yes: Results of study findings will be published.
Study at a glance
From the registry record, last updated by the sponsor on 17 Jul 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Observational Study to Assess Disease Symptoms and Progression in Participants With Sanfilippo Syndrome Type C (Mucopolysaccharidosis Type III [MPS III] C)
- ClinicalTrials.gov ID
- NCT07712003
- Acronym / sponsor ID
- C-RARE / JLK-448
- Keywords
- Mucopolysaccharidosis, Sanfilippo syndrome, MPS IIIC
- Study type
- Observational
- Recruitment status
- Not yet recruiting
- Enrolment
- 35 participants (estimated)
- Lead sponsor
- Phoenix NestIndustry (pharma, biotech, devices)
- Collaborators
- National Institutes of Health (NIH)
- Study start
- 1 Nov 2026 (estimated)
- Primary completion
- 1 Nov 2028 (estimated)
- Study completion
- 1 Feb 2029 (estimated)
- First posted
- 17 Jul 2026 (actual)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
This is a REMOTE prospective observational study of participants with MPS IIIC.
No investigational medicinal product will be administered as part of this study.
Patients functional abilities will be captured using video recordings taken by patients legal representative or caregiver using a dedicated clinical video application downloaded from the internet onto a smartphone. The video application is called C-RARE.
Electronic observer-reported outcome (ObsRO) questionnaires will be completed by the legal representatives or caregivers via C-RARE.
The study will last two years with videos and questionnaires taken every 6 months for a total of 5 time points. Data will then be reviewed and measured for functional change using a scoring scale designed for the use of this study.
Detailed description
The study will be conducted remotely; no in-person visits are required. Approximately 35 participants with MPS IIIC will be enrolled in the study through a study site in the United States of America (USA). Enrollment of the first 25 participants with age ≤10 years will help ensure that the data collected from these younger participants will provide a better understanding of the early phase of the disease that may be relevant for future drug development. The remaining 10 participants will be between 11 to 25 years of age. The cutoff for the study is 25 years old. Participants speaking either Spanish, Portuguese, German, French or English may enroll in the study.
At Screening (Visit 1), the site coordinator based at UT Southwestern will review the laboratory report with a confirmed diagnosis of Hgsnat-deficiency MPS IIIC and a mutational analysis report demonstrating homozygous or compound heterozygous, pathogenic, and/or potentially pathogenic variants in the Hgsnat gene to assess the eligibility of the participants. After confirming diagnosis by the site coordinator, the caregiver or legal representative(s) will read and sign the informed consent form electronically, and when possible, the participant will provide adult or pediatric assent electronically.
At Baseline (Visit 2), the legal representative(s) or caregiver will be asked to complete electronic demographics and medical record questionnaire via the C-RARE App.
At Baseline (Visit 2) and at 6-month intervals (from Visit 3 through the end of the study), the legal representative(s) or caregiver will be asked to complete questionnaires and record home video assessments using a dedicated study app called C-RARE. Functional and cognitive abilities will be captured in the home environment by video and PEDI-CAT, an electronic a caregiver reported outcome assessment.
The legal representative(s) or caregiver will be provided with a C-RARE kit (via mailing), which includes a manual and props, as well as training for using the app. Baseline at-home visit (demographics, medical/surgical history, concomitant medications/therapy history, video and PEDI-CAT assessment, and ObsRO) should be completed at Visit 2. At-home Visit 3 to Visit 6 (video, PEDI-CAT assessment, and ObsRO) should be completed within a 14-day period for each visit. The legal representative(s) or caregiver will be provided with the timeline for each visit.
The study population will include participants with a confirmed diagnosis of MPS IIIC. Participants will be recruited for approximately 3 months by patient organizations. The patient organizations will provide participants with details of the site coordinator at UTSW. Participant-level data will be obtained through C-RARE app and PEDI-CAT.
Study design
- Observational model
- Case only
- Time perspective
- Prospective
Who may qualify
- Ages
- 1 year to 25 years
- Sex
- All
- Healthy volunteers
- Not accepted
- Age groups
- Child, Adult
- Study population
- The study population will include participants with confirmed diagnosis of MPS IIIC. Participants will be recruited for approximately 3 months by patient organizations. The patient organizations will provide participants with details of the site coordinator at University of Texas Southwestern (UTSW).
Key inclusion criteria (4 listed)
- 1. ≥1 year and ≤ 25 years of age 2. Confirmed diagnosis of MPS IIIC by all of the following:
Key exclusion criteria (2 listed)
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Primary outcome
Daily living functions captured by video
Time frame: Baseline to up to 2 years with 6-month time points.
Ability to perform activities of daily living.
Expressive and receptive language assessed by standard questionnaires
Time frame: Baseline to up to 2 years with 6-month time points.
Ability to understand, comprehend and respond to communication.
Speech as assessed by standard questionnaires
Time frame: Baseline to up to 2 years; with 6-month time points.
Analysis of speech quality.
Behavior as assessed by ability to perform daily functions as captured by video
Time frame: Baseline to up to 2 years with 6-month time points.
Quality of behavior as defined by ability to perform defined functions
Mobility as assessed by video and standard questionnaires
Time frame: Baseline up to 2 years with 6-month time points.
Assessment of fine and gross motor abilities
3 secondary outcomes
What Matters Most
Time frame: Baseline up to 2years with 6-month time points.
Assessment of Behavioral Changes in Sanfilippo (ABCS)
Time frame: Baseline up to 2 years with 6-month time points.
PEDI-CAT standard questionnaire
Time frame: Baseline up to 2 years with 6-month time points.
Results and safety
This study is still under way. Results are not available in the source record yet.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 17 Jul 2026.
- Individual participant dataSharing planned: Yes. Results of study findings will be published.
Related trials for Sanfilippo Syndrome Type C
Enrolling by invitationObservational study
ScreenPlus: A Comprehensive, Flexible, Multi-disorder Newborn Screening Program
Acid Sphingomyelinase Deficiency, Ceroid Lipofuscinosis, Neuronal, 2
Active, not recruitingObservational study
Early Check: Expanded Screening in Newborns
Spinal Muscular Atrophy, Fragile X Syndrome
RecruitingObservational study
Natural History Study of Participants With Sanfilippo Syndrome Type IIIC
Sanfilippo Syndrome Type C
Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part.
Alyssa Boudreau contact
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
An observational study of Sanfilippo Syndrome Type C and Mucopolysaccharidosis (MPS) IIIC, run by Phoenix Nest at 1 site in United States.
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 4 inclusion and 2 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: opening soon, as of the sponsor's last update on 17 Jul 2026. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 1 site in United States. Whether a site is taking part right now should be confirmed with that site. See every site.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
Are results available for this study?
This study is still under way. Results are not available in the source record yet.
How can a doctor refer a patient or contact the research team?
Contact Holly Lawrence (2144044239, Holly.Lawrence@utsouthwestern.edu), or a site near the patient. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Daily living functions captured by video (time frame: Baseline to up to 2 years with 6-month time points.). The study lists 5 primary outcomes in all. It is what the study was designed to measure, not a finding.
Where can I read the original study information?
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 17 Jul 2026.